Yes, really. They up and dropped an entire HDMI mode used by "older" 4K displays.

A cynic would say they wanted to boost sales on newer displays, but it seems more likely that a bug of some kind came up in a driver (I was unaware of any problems, but that's hardly proof of anything) and they just decided it was easier to cut support of those displays than to fix the problem.

Support forums filled with complaints by the dozens of pages, but Sony didn't care, because why should they? I'm sure somebody did the calculation that said we weren't a big enough demographic to matter.